Street Tree Requirements

Do you require developers to install street trees? Please share.

Our code is wierd. We require them, but not in the right-of-way. They go in a 5' wide street tree easement that parallels the edge of right-of-way. The plat annotates that they are to be maintained by the home owner, and there are penalties for not replacing a dead tree, or for allowing a hazard tree to remain. So basically, the City Forester becomes a 'Tree Cop' instead of a maintenance worker.

We have approved species lists which do not include non-native species (the ever popular Norway Maple is prohibited!), and the list is divided into small, medium, large, and park-suitable (species of conifers, nut bearers, etc). Spacing requirements vary depending on size of species selected.

Here's my quandry: Our forester prefers species diversity to avoid mass die offs such as Dutch Elm or Oak Wilt. I agree, but have a differing opinion as to implementation. He prefers no more than 3-5 linear plantings to be the same species, then switch. I prefer one species on a block to provide a uniform canopy upon maturity, and alternate species block by block.

The street tree easement is not that uncommon anymore. With most utilities now being put underground, there needs to be a separation.

Most stuff I've dealt with, requires the developer to replace anything that dies with 1-2 years of planting, thus helping with the "mass die off" issue. If a tree is not going to take it is within the 1-2 years after planting that it will die.

In my experience, mass die offs are the result of a diseased lot of trees, unskilled arborists planting them ,etc.

FWIW, I too prefer one species per street, just looks nicer when the trees grow up.

I'm actually thinking about getting an LA degree. Further pertinents to follow in other threads.

We require them in the terrace every thirty feet. There is no list of accepted species, but they do have to be approved by the forester and must be a minimum 2.5" caliper (5 cm). I also favor a uniform planting across a length of street. The 3-tree, 3-tree, 3-tree approach is not anywhere nearly as attractive as a uniform block, or alternating trees. I am partial to alternating contrasting foliage in larger applications, such as 800' of frontage on an industrial site. Alternating sugar maples and quaking aspens, for example, provides nice red-yellow contrast in fall, and green-silver tones in summer. The slightly different forms, height, and bark colors and texture add a little more interest.

We require that developers place trees in a ROW every 50 feet or in clusters (we call them parkway trees) and around the interior perimeter of the site and we require 1 tree per 10 parking spaces for parking lots

We separate out the species into large, med, and small.

For developments requiring 20 or more trees, no more than 20% of the trees can be of one species and no more than 10% of street trees can be of one species.

Street trees shall be planted in a sequence using all approved species in an alternating fashion, or with no more than 6 of the same species being planted in succession.

I don't interface with our Subdivision code often, but I agree with 'one species, per block'

One species per block does look nice, but unless prevented by some sort of barrier (I'm not sure if sidewalk concrete goes deep enough to prevent this) if trees of the same species are planted next to each other their root systems eventually begin to merge. Some trees are much more prone to this than others, American elms, for example, which is one of the things that made it so vulnerable to mass die-offs--once one tree gets the spores in it from an uncleaned tool, any other trees with even one root fused to it can get it, and the whole street can lose its elms. With all the new diseases busting out in the last several years, it's probably safest to insist on alternating species (and don't alternate two closely related species, like sugar maple with red maple; diseases, especially viral and bacterial ones, have a nasty habit of jumping from one species to close relatives). There are lots of combinations that still look nice together--I like cardinal's suggestion of sugar maple and quaking aspen. Local nurseries/garden stores, arboreta/botanical gardens, foresters, state DNRs/DOEs (environment, not energy) are good bets for suggestions.

Laid out by Olmsted, Charlotte's early suburbs benefited from the regularly-spaced planting of a single tree species, the willow oak. This is the species that God plants naturally around Charlotte (to some, this is a pretty good working definition of a weed). The trees were ripped from the adjacent forest and transported by mules to be planted close together, already forty feet high though narrow in their branching --as forest trees normally are.

Liberated, these trees grew towards each other over the roadways, creating lofty cathedral-like canopies over the streets: cool, shady tunnels that created their own microclimatic zone in this hot, humid city. The result was enchanting, and everyone who visited Charlotte commented on these trees. They didn't say, "I like Charlotte because it has lots of trees," they said instead: "What is that tree??"

For indeed Charlotte was unique, due to Olmsted's prescience. No other city known to me has this particular magnificent tree cover, 100 feet of gracefully arching parasols, finer even than the vaunted elms that used to grace Commonwealth Avenue or the New Haven Green.

Then the city hired a slick landscape consultant from out of town. They paid an inordinate and astronomical fee for the following thrice-familiar pearl of wisdom: plant a variety of trees, so that if a disease breaks out in one species, you will not lose all your street trees.

The city implemented this banal insight as policy, and now Charlotte is experiencing in slow motion an aesthetic disaster as great as the one that probably would never have occurred. After ninety years without disease, trees that die of old age are being replaced by a variety of humdrum species, and Charlotte is beginning to resemble every other place.

Just goes to show: if you plan for disaster, you just might get one, though not necessarily the one you expect.

Originally posted by ablarc For indeed Charlotte was unique, due to Olmsted's prescience. No other city known to me has this particular magnificent tree cover, 100 feet of gracefully arching parasols, finer even than the vaunted elms that used to grace Commonwealth Avenue or the New Haven Green.

The American Elm grew much the same way. I remember as a kid in the 1970's making my mother drive home from the library down the "church" street. I was as glorious as any medieval cathedral. Sadly, they are all gone.

I would still agree with you in replacing the historic willow oaks with willow oaks. Yes, there is a risk. It is still worth it.